1. Field of the Invention
This invention relates to the field of gas delivery masks. More specifically, the present invention comprises a mask that fits comfortably over a user's head and face in order to maintain an open airway in the respiratory system of the user. The mask is suitable for use in a continuous positive airway pressure system.
2. Description of the Related Art
A continuous positive airway pressure (“CPAP”) system is used in order to keep a user's airway open in situations where the user's body is incapable of this task. A CPAP system typically includes a CPAP machine, plastic tubing, a mask, and sometimes a humidifier. The CPAP machine contains a series of filters, a motor, a fan, and other components. The motor and fan assembly pumps ambient air into the CPAP machine. Typically, that air travels through at least one filter. In some cases, the CPAP machine contains a humidifier or is connected to one. After moisture is added, the air travels through plastic tubing to the gas delivery mask. The mask may fit over the user's nose and mouth or fit into or over the user's nostrils. By sealing the passageway of the air from the CPAP machine to the user's lungs, the CPAP machine can maintain a constant pressure within the user's lungs that is greater than the ambient pressure. (Here, the system is the users lungs, airway, mask, tube, and CPAP machine.) The pressure maintained in the system provides a continuous expanding force on the user's airway, thereby sustaining an open airway.
There are multiple applications for a CPAP machine. Oftentimes, a CPAP machine is used to assist a patient who has respiratory or heart problems. This includes preterm infants with underdeveloped lungs and other patients having respiratory emergencies either in a hospital or in an ambulance. Although CPAP machines are now very common in intensive care units for such emergencies, the most common use of a CPAP machine is to alleviate sleep apnea.
Sleep apnea affects the quality of life of many individuals. Someone suffering from sleep apnea is constantly awoken during the night due to the airway closing while the patient is asleep. This leads to many symptoms including loud snoring, sore or dry throat, sleepiness during the day, forgetfulness, and drastic mood changes. A person suffering from sleep apnea is constantly drowsy because he or she is constantly being awoken during the night. In addition, athletes or other individuals have issues gaining or losing weight because the natural sleep cycle is interrupted.
A CPAP machine and mask can be used to maintain an open airway for a user, which allows the user to sleep without being constantly awoken by the closed airway. Unfortunately, sleeping with a mask over one's face can be uncomfortable. In addition, a typical gas delivery mask places a significant amount of force on the user's cheek bones that can eventually cause jaw displacement, cheek deformation, and facial nerve damage. In addition, many gas delivery masks apply significant pressure to the face near the cheekbone. This pressure applied to the cheeks can cut off circulation below the eyes, thereby reducing blood flow to the corners of the eyes, as well as some facial nerves. Straps used to secure such masks can reduce blood flow to the area above the eyes and the outside corner of the eyes. In some cases, the blood flow is almost completely cut off to the eyes. While this is dangerous for any patient, it is extremely risky for patients with eye diseases or disorders. These issues may cause users to discontinue use of the CPAP machine and mask, which causes the symptoms to continue. Either the patient discontinues use or continues to use the mask which can cause other long term damage. Therefore, finding a comfortable mask for a user is important in order to treat his or her disorder.
FIG. 1 shows prior art CPAP system 10, which is used for treating sleep apnea. CPAP system 10 includes CPAP machine 12, ventilation conduit 14, and prior art gas delivery mask 23. CPAP machine 12 includes ventilation unit 18 and humidifier unit 20. Ventilation unit 18 draws air from the ambient environment through air intake 22. That air is pulled through several filters (not shown) by means of a fan and motor assembly (also, not shown). The air is then pumped through humidifier unit 20 in order to increase the moisture in the air. Often patients have issues with an irritated or dry throat when the air is not humidified so some units include a humidifier. Once the air contains a sufficient amount of moisture (this is typically adjusted by the user), air is forced through ventilation conduit 14. Ventilation conduit 14 is attached to gas delivery mask 23, which is attached to the face of the user.
FIG. 2 shows a prior art full face gas delivery mask 23. In order to keep full face mask 23 fastened to the user's face 68, heavy duty straps 25 are attached to full face gas delivery mask 23. Straps 25 fasten behind the user's head 70, as shown in the figure. The reader will note that there are many techniques to fasten straps 25 in order to retain full face mask 23 attached to user's face 68. For example, full face mask 23 may fasten behind the head using VELCRO. The reader will also note that many different configurations of straps can be used as well. The mask configuration illustrated in the figure shows a very common type of mask. One important aspect discussed briefly in the preceding text is the impact the straps have on the user. Reduction of blood circulation to the eyes was discussed, but there are other complications as well. For example, there is typically a strap that wraps around the user's head, over the forehead, and just above the eyes. This strap can reduce circulation to the brain causing compromised cerebral blood flow—oftentimes a more serious complication than the reason for using the mask.
There are four primary disadvantages to using a full face gas delivery mask. First, straps 25 are necessarily heavy duty in order maintain the position of mask 23 on user's face 68. Second, the interaction between lip 27 and user's face 70 is preferably sealed in order to maintain pressure in the user's lungs and airway. In order for that seal to remain intact, straps 25 should be relatively tight. The tightness of straps 25 and the relatively firm material of mask 23 often cause discomfort for the user. Straps 25 and lip 27 oftentimes press against user's face 68 in a manner that not only causes discomfort, but can cause nerve damage, temporary paralysis of the face, and other complications. In fact, full face mask 23 causes such discomfort that many users discontinue sleep apnea treatment after a very short time.
Third, individuals with an oddly shaped facial structure, beards and other facial hair often have issues maintaining pressure in the lungs and airway because the face 68 and lip 27 cannot maintain a seal due to the interference of the hair or facial structure. Fourth, the tightness and position of straps 25 may cause more serious complications—such as causing (or worsening) eye disorders or disease, disturbance of cerebral blood flow, compromise of blood flow to the eye and corner of the eye, and other serious issues.
Thus, inventors have explored techniques to fabricate a gas delivery mask that is more comfortable and less intrusive. An example of this approach is found in U.S. Pat. No. 7,938,116 to Ging (2011). The Ging device provides a mask and head gear unit that includes several straps which cover much of the user's face and head. Similarly, U.S. Pat. No. 8,286,636 to Gunaratnam provides a number of straps that cover the user's head and face. In addition, the Gunaratnam device oftentimes includes rigid pieces resting against the user's face or head.
Although these devices provide a gas delivery mask and headgear to support that mask, they fail to provide a minimalist design that does not sacrifice comfort. The present invention solves this and other problems, as will be described more particularly in the following text.